1. Field of the Invention
This invention relates generally to latch constructions, and more particularly to devices of a type adapted to be permanently carried on a door or panel and which can be manually operated to selectively secure or release the panel from an underlying support structure.
2. Description of the Related Art Including Information Disclosed Under 37 CFR .sctn..sctn.1.97-1.99
U.S. Pat. No. 4,759,204 illustrates a locking mechanism having a body, a rotor, an operating arm and a piston. The piston is normally spring biased into engagement with the operating arm, and keys the operating arm to the body, against rotation. When a suitable key is inserted into the rotor and depressed, it retracts the piston in the body so as to release the keying between the operating arm and body and simultaneously keys the rotor to the operating arm, so as to enable the rotor and key to turn the arm toward an unlocking position. A relatively large number of moving parts is employed, involving multiple spring-biased tumblers and complicated structural parts that require special machining operations which result in considerable manufacturing expense. Assembly is similarly complex to the extent that it is both time-consuming and costly from the manufacturing standpoint.
A panel locking device is shown in U.S. Pat. No. 1,938,339. The disclosed lock is intended for use with sliding panels, as in showcases of the type employed to store and display various types of merchandise. The lock includes a spring biased cylinder and spring biased tumbler pin, which latter can be retracted by manual insertion of a suitable key into the cylinder. No turning of the key is required to unlock the device.
Both of the locks noted above are of a security type whose function is to prevent entry or access by unauthorized personnel. As a consequence, there is had involvement with special keys and lock cylinders of the kind having tumbler mechanisms, which are both complex and costly. With certain applications, security is not a prime consideration; instead, simplicity and reliability, as well as freedom from malfunction are the main considerations, as for example where it is desired to have a latch which is highly reliable and not prone to accidental or inadvertent release under the conditions to which it is subjected.
In the past, where efforts have been made to simplify latch structures, the results have often led to units which inherent have loosely-fitting parts that are subject to noise or rattling, excessive wear, etc. under conditions of vibration. Such characteristics have been found to be objectionable for many applications where vibration is routinely encountered, such as in internal combustion engines, aircraft/rocket engines, industrial machinery, and the like.